This invention relates to a circuit for lighting like a candlelight, and more particularly to a circuit which can continuously and irregularly vary luminous intensity of a light emitted by the circuit.
An illuminating device which uses a candle or candles has a little utility because of possibility of breaking out of a fire and a limited lighting time of a candle. Many of illuminating devices of such kind have been changed to devices having electric lamps. But, such illuminating devices are irksome, because an electric lamp cannot easily vary luminous intensity of a light emitted by the lamp.
Therefore, electric lighting devices which can change luminous intensities have been developed using mechanical or electrical methods. In the mechanical methods, the devices become complicated and expensive structures. In the electrical methods, it is not possible to obtain a device which can continuously and irregularly vary luminous intensity of a light. A device which has a plurality of electric lamps in an envelope and can change number of lighting lamps is known. A device shown in U.S. Pat. No. 3,710,182 has an incandescent lamp and a thyristor being connected in series across an alternate current source and an oscillator supplying gate pulses to the thyristor to energize the lamp. The device can vary luminous intensity of a light only constantly or periodically.